Current approaches to macromolecular crystallization

Given our current expertise, and the certain future devel-opments in genetically altering organisms to produce proteins of modified structure and function, the concept of protein engineering is nearing reality. Similarly, our ability to describe and utilize protein structure and to define interactions with ligands has made possible the rational design of new drugs and pharmacological agents. Even in the absence of any intention toward applied use or value, the correlation of regulation, mechanism, and function of proteins with their detailed molec-ular structure has now become a primary concern of modern biochemistry and molecular biology. At the present time, there are numerous physical-chemical approaches that yield information regarding macromolecular structure. Some of these methods, such as NMR and molec-ular dynamics, are becoming increasingly valuable in defining